A turbocharger for an internal combustion engine can include an input side and an output side. The input side includes a turbine chamber that receives exhaust gas from the engine. A turbine in the turbine chamber turns when exhaust gases from the engine flow through the turbine chamber. The output side includes a compressor chamber that receives fresh air. A compressor blade in the compressor chamber is coupled to the turbine by way of a shaft, and the compressor blade turns when the turbine turns. Generally, a speed or load of the engine determines how quickly the turbine spins. As a volume or velocity of exhaust gases increases, such as at higher engine speeds, the turbine and the compressor blade turn more quickly.
A turbocharger can include a wastegate in the turbine chamber. A wastegate is configured to selectively bypass or discharge some exhaust gasses from the turbine chamber, thereby decreasing a pressure in the turbine chamber, and thus reducing a turbine velocity. A wastegate can be controlled by a compressor manifold pressure, sometimes referred to as boost pressure. When the boost pressure exceeds some specified maximum pressure, the wastegate can open a door in the turbine chamber to release gas from the chamber.